1. Field of the Invention
The present invention relates to a method for controlling additional service functions, in which data is transmitted to at least one terminal in either a telecommunications network or a communications network using at least one identifier. The identifier identifies a connection in a first connection model.
2. Description of the Prior Art
A method such as that described above is standardized, for example, in the following ITU-T International Standards (International Telecommunication Union-Telecommunication):
H.323 (02/98) Packed Based Multimedia Communications Systems,
H.225.0(02/98) Call Signaling Protocols and Mediastream Packetization for Packed-Based Multimedia Communications Systems, and
H.245(05/99) Control Protocol for Multimedia Communication.
The connection model on which these Standards are based defines an identifier, called CallID, which uniquely identifies a connection between two terminals. Other identifiers are used for conference circuits including a number of terminals, for example the identifier ConferenceID.
Based on the H.323 Standard, a number of additional service functions have been standardized:
H.450.1(02/98) Generic Functional Protocol for the Support of Supplementary Services,
H.450.2(02/98) Call Transfer Supplementary Service for H.323,
H.450.3(02/98) Call Diversion Supplementary Service for H.323,
H.450.4(05/99) Call Hold Supplementary Service for H.323,
H.450.5(05/99) Call Park and Call Pickup Supplementary Services for H.323,
H.450.6(05/99) Call Waiting Supplementary Service for H.323,
H.450.7(05/99) Message Waiting Indications Supplementary Service for H.323.
The cited additional functions have been developed on the basis of the connection model defined in the H.323 Standard. This connection model is very simple, but is not suitable for all applications.
An object of the present invention therefore, is to specify a simple method for controlling additional service functions wherein it is possible to control even those service functions for which the first connection model is suitable only to a limited extent. Furthermore, the present invention has the aim of specifying an associated communications network and an associated program.
Accordingly, the present invention is based on the knowledge that there is a preferred connection model for each service function which, when used, allows the service function to be carried out in a very simple manner. Thus, for example, ECMA Standard (European Computer Manufacturer Association) xe2x80x9cServices for Computer Supported Telecommunications Applications (CSTA) Phase IIIxe2x80x9d, Section 6.1.5 explains a connection model in which there is a joint call between two terminals. A first connection exists between the first terminal and the call. A second connection exists between the call and the second terminal. The connections are uniquely identified by the units identifier of the unit involved with the connection and by a call identifier for the relevant call. Although this connection model is more complex than the connection model defined in the H.323 Standard, it is more suitable for carrying out certain service functions. For example, a portion of the identifiers can be retained for call forwarding. If, for example, only two connection models are considered, then these connection models can each be assigned a number of service functions for whose implementation one connection model or the other is more suitable.
The present invention is furthermore based on the knowledge that it is simpler to comply with a number of Standards via additional measures than to add the service functions of the other Standard to one Standard. Specifically, it often takes a number of years to work out or revise a Standard.
For this reason, in the method according to the present invention, the identifier provided in the first connection model is converted to at least one identifier which is used to identify a connection according to a second connection model. The connection models and the respective identifiers as well differ from one another in their layout and/or in their value. The second connection model is provided for controlling additional service functions of the terminals from a computer which is not itself associated with any terminal. Control such as this is also referred to as third party control. In the method according to the present invention, the functionality of the terminals is expanded by at least one additional service function, using the identifiers provided in the second model.
Basic functions of the terminals, for example setting up and clearing connections, are those controlled according to a first connection model. Certain additional service functions are controlled according to a second connection model. The conversion of the identifiers makes it simple to change from one connection model to the other connection model. The method of the present invention allows one method to be used in each case for different service functions, which is based on a different connection model; namely on a connection model which is the most suitable.
In an embodiment of the present invention, the data transmitted in the telecommunications network contains data of different media types; in particular, voice data and/or picture data and/or program data. The first connection model is thus used for the transmission of multimedia data. One widely used Standard for such transmission is the H.323 Standard defined by the ITU-T (International Telecommunication Union-Telecommunication).
In a further embodiment, the identifier defined in the first connection model is a connection identifier, called CallID which identifies an existing connection or a connection which is to be set up between at least two terminals. The connection identifier has one part. There is no relationship with one terminal, or even with both terminals involved in the connection.
Additionally or alternatively, the second connection model for controlling additional service functions of the terminals in a telecommunications network from a computer is likewise defined in accordance with an international Standard, in particular in accordance with the CSTA Standard from the ECMA; for example, in accordance with the CSTA III Standard. However, other Standards are also used in the development; for example the TAPI Standard (Telephone Application Programming Interface) from MICROSOFT or the JTAPI Standard from SUN.
In another embodiment, the identifier defined in the second connection model contains a first part for identifying a terminal involved in the connection and a second part for identifying the call affected by the connection. A connection model such as this is defined, for example, in the CSTA Standard.
In another development, the additional service function relates to automatic call distribution from a central terminal for central selection of receiving terminals for receiving calls. Until now, automatic call distribution has been used mainly for terminals for voice transmission in so-called call centers. This refinement extends the application area of automatic call distribution to multimedia terminals as well which are actuated using a method which is based on a different connection model than that defined, for example, in the CSTA Standard.
In a refinement of the additional service function call distribution, feeder programs are executed in both the central terminal and each of the receiving terminals. When a feeder program is executed, messages are interchanged with a central conversion program which operates as an interface between a control computer for controlling the call distribution and between terminals to be included in the call distribution. The feeder programs are also referred to as deputy programs. The name Marshall program is used for the conversion program. A protocol which is based on the protocol used for call distribution is used for communication between the feeder program and the conversion programs. The concept of a conversion program and feeder programs allows terminals which actually need to be actuated using a different protocol to be actuated, nevertheless, using a protocol which is suitable for call distribution. In this context, reference is made to the German Patent Application with the Application Number 19947032.4.
In an embodiment of the present invention, the identifiers are converted during execution of the central conversion program. There need, therefore, be only one of these programs for conversion of the identifiers in this refinement. The terminals need not themselves convert any identifiers. In the same way, no identifiers need be converted in the control program for call distribution.
The calling terminals may, but need not, contain a feeder program. In one development, calls arriving from terminals without a feeder program are distributed using the same method as calls arriving from terminals with a feeder program. This is possible since a calling terminal need not be actuated using a method which is based on the second connection model. The calling terminal can be actuated using a method which is based on the first connection model; for example for call forwarding.
In another development, when a feeder program is started, a registration message which contains a data item for identifying the transmitting terminal is in each case transmitted to the conversion program. This measure results in the conversion program being informed about terminals which can be included in the call distribution.
In one refinement of the present invention, the conversion program transmits the identifiers of selected terminals, or of all the registered terminals, to the control program. This is done automatically or in response to a request coming from the control program. The control program can use the identifiers to decide which terminals it wishes to monitor. The selected terminals are monitored, with the conversion program passing on to the control program the messages which arrive from the units being monitored. The central terminal always needs to be monitored. In one refinement, a protocol is used between the terminals and the conversion unit, which is based on a protocol based on the second connection model. The CSTA III Standard is particular suitable for use as a basis for this.
In a further embodiment, a distribution program is used between the conversion program and the control program, and controls the passing on of messages as a function of destination presets. A program such as this is executed, for example, on a telecommunications server. The messages are passed on using program identifiers and/or domain names. Thus, in a development, messages arriving from the control program are passed on to the conversion program using an identifier which is produced by the control program and which denotes the conversion program. Messages arriving from the conversion program contain an identifier which was previously transmitted from the control program to the conversion program in a message for monitoring a specific terminal.
In another development, a call receiving program is executed in the receiving terminal. Messages produced during the execution of the call receiving program are passed on via the distribution program to the conversion program. Messages which are also required for controlling call distribution are also passed on to the control program. Passing the messages on to the conversion program means that the conversion program is aware of all the active terminals as well as all those units which are suitable for receiving calls. If a receiving terminal later becomes busy, then the conversion program can itself produce an appropriate message and transmit this to the control program; for example the event message xe2x80x9cEvent AgentBusyxe2x80x9d.
In one refinement, call distribution is carried out as follows. First of all, a call to the central terminal is processed using a method based on the first connection model; for example, in accordance with the H.323 Standard or in accordance with the H.225 and H.245 Standards which are linked to this Standard. In addition to the method steps encompassed by this Standard, the central terminal transmits a message, which signals the selection of the central terminal, via the conversion program to the control program. This message is, for example, the xe2x80x9cEvent Deliveredxe2x80x9d message defined in the CSTA III Standard. After the control program has received the message which signals this selection, this program transmits to the central terminal a message for call diversion to a receiving terminal. This message is, for example, the CSTA III message xe2x80x9cDeflectCallxe2x80x9d or a message xe2x80x9cDMDeflectCallxe2x80x9d based on this. The call diversion itself is then carried out using the method based on the first connection model, that is to say, for example, according to the H.323 Standard and, in particular, according to the H.450.3 Standard. This linking of methods from different Standards results in a simple method for call distribution. Standardized commands can be used so as to avoid any new development or adaptation of Standards.
In yet another development, once a connection has been set up between the calling terminal and the receiving unit which receives the diverted call, the conversion program transmits to the control program a message which signals the operator state of the receiving unit. This message is used to tell the control program that the relevant receiving terminal is currently unavailable for call distribution.
The present invention also relates to either a communications network or a telecommunications network which is suitable for carrying out the method according to the present invention and/or for carrying out the developments and refinements of the present invention. The technical effects quoted above thus also apply to the communications network. In particular, the communications network may also include terminals on which the feeder programs are executed. The communications network according to the present invention is particularly suitable for call distribution.
Furthermore, the present invention relates to a conversion program during whose execution the identifiers of various connection models are converted. The conversion program for the first time allows the majority of the effects of the method, and its refinements, to be exploited. In one development, the conversion program is stored on a data storage medium, for example on a floppy disk, CD (Compact Disc) or a magnetic disk drive.
Additional features and advantages of the present invention are described in, and will be apparent from, the following detailed description of the preferred embodiments and the drawings.